Environmental Protection Agency § 230.42

§ 230.41 Wetlands. tion or elimination of the wetland sys- (a)(1) Wetlands consist of areas that tem can degrade water quality by ob- are inundated or saturated by surface structing circulation patterns that or ground water at a frequency and du- flush large expanses of wetland sys- ration sufficient to support, and that tems, by interfering with the filtration under normal circumstances do sup- function of wetlands, or by changing port, a prevalence of vegetation typi- the aquifer recharge capability of a cally adapted for life in saturated soil wetland. Discharges can also change conditions. the wetland habitat value for fish and (2) Where wetlands are adjacent to wildlife as discussed in subpart D. open water, they generally constitute When disruptions in flow and circula- the transition to upland. The margin tion patterns occur, apparently minor between wetland and open water can loss of wetland acreage may result in best be established by specialists famil- major losses through secondary im- iar with the local environment, par- pacts. Discharging fill material in wet- ticularly where emergent vegetation lands as part of municipal, industrial merges with submerged vegetation or recreational development may mod- over a broad area in such places as the ify the capacity of wetlands to retain lateral margins of open water, head- and store floodwaters and to serve as a waters, rainwater catch basins, and buffer zone shielding upland areas from groundwater seeps. The landward mar- wave actions, storm damage and ero- gin of wetlands also can best be identi- sion. fied by specialists familiar with the local environment when vegetation § 230.42 Mud flats. from the two regions merges over a broad area. (a) Mud flats are broad flat areas (3) Wetland vegetation consists of along the sea coast and in coastal riv- plants that require saturated soils to ers to the head of tidal influence and in survive (obligate wetland plants) as inland lakes, ponds, and riverine sys- well as plants, including certain trees, tems. When mud flats are inundated, that gain a competitive advantage over wind and wave action may resuspend others because they can tolerate pro- bottom sediments. Coastal mud flats longed wet soil conditions and their are exposed at extremely low tides and competitors cannot. In addition to inundated at high tides with the water plant populations and communities, table at or near the surface of the sub- wetlands are delimited by hydrological strate. The substrate of mud flats con- and physical characteristics of the en- tains organic material and particles vironment. These characteristics smaller in size than sand. They are ei- should be considered when information ther unvegetated or vegetated only by about them is needed to supplement in- algal mats. formation available about vegetation, (b) Possible loss of values: The dis- or where wetland vegetation has been removed or is dormant. charge of dredged or fill material can (b) Possible loss of values: The dis- cause changes in water circulation pat- charge of dredged or fill material in terns which may permanently flood or wetlands is likely to damage or destroy dewater the mud flat or disrupt peri- habitat and adversely affect the bio- odic inundation, resulting in an in- logical productivity of wetlands eco- crease in the rate of erosion or accre- systems by smothering, by dewatering, tion. Such changes can deplete or by permanently flooding, or by altering eliminate mud flat biota, foraging substrate elevation or periodicity of areas, and nursery areas. Changes in water movement. The addition of inundation patterns can affect the dredged or fill material may destroy chemical and biological exchange and wetland vegetation or result in ad- decomposition process occurring on the vancement of succession to dry land mud flat and change the deposition of species. It may reduce or eliminate nu- suspended material affecting the pro- trient exchange by a reduction of the ductivity of the area. Changes may re- system’s productivity, or by altering duce the mud flat’s capacity to dis- current patterns and velocities. Disrup- sipate storm surge runoff.

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